iPhoto is clumsy when you're using Lightroom.
That's because iPhoto and Lightroom are databases.
They can't "talk" to each together.
Therefore, there's no easy way to use both.
Your photographs are stored in the iPhoto Library folder.
This folder is a package-content folder.
It's an Apple-only folder.
Non-Apple programs can't open the folder.
Therefore, you have to "jailbreak" your photographs from this folder "jail."
Backup the photographs you have in iPhoto by exporting them.
The exported photographs won't be organized into Events.
However, you'll have your photographs in case one of the "jailbreak" programs below does something dastardly.
In iPhoto, do the following.
1) Go to File > Export.
2) Select Original in the Kind menu.
The unedited files will be exported.
4) Click Export.
5) Select the destination folder.
This writer has used this program and found it to be excellent—and only $13.
Before you perform an action on thousands of files, experiment with just a few.
This method doesn't preserve your events and other features of iPhoto.
Do the following.
1) Go to Finder > MacIntoshHD > Users > User Name > Pictures > iPhoto Library.
2) Right click on the iPhoto Library.
Can't right click with your mouse?
Press and hold Ctrl, and click your mouse button.
3) Click Show Package Contents.
You're in the iPhoto Library.
Don't delete, move, or rename anything.
The important folders are Masters (aka Originals) and Modified.
The Masters folder contains your unedited photographs.
The Modified folder contains the edited versions.
4) Right click on the Masters (aka Originals) folder and select Duplicate.
5) Drag the Masters copy folder (or the Originals folder) from the iPhoto Library to your Desktop.
6) Go to Lightroom and import the photographs from the Masters copy folder (or the Originals folder) located on your Desktop.
IPTC metadata includes information that you have added to the photograph files while using iPhoto, such as:
• Contact and copyright information.
iPhoto stores the IPTC metadata separately from the JPEG files.
Therefore, when you move your photographs from the iPhoto library, the IPTC metadata is not transferred.
To see what the IPTC metadata includes, do the following.
1) Go to the Library module in Lightroom.
2) On the right side of your screen, open the Metadata panel.
3) Open the menu at the top of the panel and select IPTC.
You probably have not added any essential information.
If you have, do the following.
Savvy computer users can use ExifTool to write the IPTC metadata to their JPEG files.
Not-so-computer-savvy users can add their contact and copyright information using Lightroom.
Captions, and other information distinctive to each file, are not easily added later.
Exporting From iPhoto (March, 2013)